1. Field of the Invention
The present invention relates to a molded gasket according to a sealing technique, and more particularly to a method for producing the same.
2. Description of the Conventional Art
Conventionally, there has been known a molded gasket (a GDL integrated seal) structured such that a gas diffusion layer (GDL) is inserted into a metal mold, and a gasket body constructed by a rubber-like elastic body is integrally formed with the GDL according to an injection molding. A micro porous layer (MPL) treatment is generally applied to the GDL mainly for the purpose of water management, and the rubber can be integrally formed with the MPL treated GDL.
FIGS. 13A and 13B show an example of this kind of prior art, a GDL 11 is provided as a substrate, and an MPL layer 12 is provided as a surface treated layer on one surface 11a in a thickness direction of the GDL 11. Further, a gasket body 13 constructed by a rubber-like elastic body is integrally formed as a rip-like element on the other surface 11b in the thickness direction of the GDL 11.
In producing the molded gasket (the GDL integrated seal), molded pieces after a primary vulcanization are placed and arranged on a placement stand 31 such as a net rack or the like normally by setting the one surface 11a in the thickness direction of the GDL 11 having the MPL layer 12 downward, as shown in FIG. 14. The molded pieces are not arranged by setting downward the other surface 11b in the thickness direction of the GDL 11 with which the gasket body 13 constructed by the rubber-like elastic body in the opposite side is integrally formed, for preventing foreign material from attaching to the gasket body 13 from the placement stand 31, preventing the gasket body 13 from being polluted, and preventing a pattern of the placement stand 31 from being transcribed to the rubber (for example, preventing a net pattern from being transcribed to the rubber, in the case of the net rack).
However, in the case of arranging by setting downward the one surface 11a in the thickness direction of the GDL 11 having the MPL layer 12 as mentioned above, the MPL layer 12 comes into contact with the placement stand 31. Accordingly, there is a risk that problems such as the foreign material attachment, the pollution and scratching may be generated in the MPL layer 12. Therefore, in order to dissolve the problems, a resin protection sheet 32 has been conventionally put on the placement stand 31 as illustrated, and the molded pieces have been arranged on the sheet 32. As the protection sheet 32, a non-electrostatic property (dust prevention), a non-staining property and a heat resisting property (at a time of a secondary vulcanizing step) are required, and it is necessary to select a very expensive material. Further, it is necessary to periodically wash and replace, and a yield ratio is lowered, thereby causing a cost increase.